I have been taking metoprolol tartrate 25mg 1/2 tab twice a day for 30 days. Is it ok to stop?

I am 42 with no history of heart problems and went to the emergency room on 8/22/10 with fast heart rate (135bpm standing still with 145/90) and feeling like my heart was skipping beats. (It actually felt like someone tapping on my chest several times a day for two weeks prior.) I stayed overnight and they did all the test and said that my heart is doing fine by all the stress test and such, but that I'm having palpitations. So they gave me a whole 25mg Metoprolol Tartrate with a prescription for the same to be taken over the next 30 days, 1/2 at 9am and 1/2 at 9pm. It's been 3 weeks and my heart rate average is down to 70-80+bpm (but as high as 100bpm) and 120/70 with sometimes (over the last 4 days) down to as low as 92/60. I was supposed to follow up with a doctor but my insurance application won't go thru until 10/16/10 and the emergency doctor has denide refills. I see that heart damage and even heart attack can happen if this medication is stopped suddenly. I was wanting to know if since I've only been taking it for 30 days at 1/2 in the am and 1/2 in the pm, and a relatively low dose of 25mg, am I endanger of heart damage and/or heart attack; or is that for people who have taken it for longer periods of time at the same or more dosage?